[Hematopoietic stem cells II. Diagnostic and therapeutic aspects]

Characterization and isolation of haematopoietic stem cells (HSC) have resulted in their clinical application in patients with malignant disorders and--through gene therapeutic initiatives--also in the treatment of inherited diseases. Autologous stem cell transplantation (ASCT), which was introduced because of the high number of relapses in cancer patients in remission, involves dose-intensification (conditioning), which induces myeloablation. In this setting, reinfusion of HSC is performed to restore haematopoiesis. Flow cytometric determination of CD34+ cells and clonogenic assays for committed myeloid HSC (CFU-GM) are vehicles for quality control of the harvested HSC material and are integrated into the ASCT programs. Moreover, harvest of HSC and purification of CD34+ cells enables new treatment options such as removal of cancer cells from grafts, optimization of gene transduction as well as ex vivo expansion of HSC before reinfusion. In conclusion, the expanding insights into HSC in the 1990's have already been translated into valuable diagnostic and therapeutic modalities.